The fate of Moss' character Peggy Olsen was left up in the air at the end of Season 5, with her leaving Sterling Cooper Draper Pryce behind for greener pastures. Things only got worse when cast member Jared Harris — who definitely won't be back (RIP, Lane!) — hinted that Moss had also said her goodbyes. Moss recently confirmed to TVGuide.com that she would return for Season 6.

In addition to Moss, Jones and Kartheiser — the latter two portray Betty Francis and Pete Campbell — Christina Hendricks is still negotiating her deal, though the details of how long she'd be portraying the vivacious Joan Holloway are unclear. Leading man Jon Hamm previously signed a deal that would see him stick with the show through Season 7.

Mad Men heads is slated to begin production on its sixth season in October.